The Beryl Field, Block 9/13, UK North Sea
The Beryl Field is located within Block 9/13 in the UK North Sea, in the west central part of the Viking Graben. The block was awarded in 1971 to a Mobil operated partnership, and the 9/13-1 discovery well drilled in 1972. The Beryl A platform was installed in 1975 and oil production started up the following year. The Beryl B platform was added in 1983 and production and gas re-injection pressure support commenced in 1984. The first 3D seismic survey was shot over the field in 1986, and the most recent in 1997. As of January 1999, 133 wells have been drilled into the field and development drilling is expected to continue well into the twenty-first century.
Commercial hydrocarbons occur in sandstone reservoirs ranging in age from Triassic to late Jurassic, with the primary reservoir being the Middle Jurassic Beryl Formation (1.4 billion barrels of oil originally in place). Total ultimate recovery for all reservoirs in the field is expected to be about 960 million barrels of oil (MMBBL) and 2.1 trillion cubic feet (TCF) of gas. As of January 1999, the field has produced nearly 710 MMBBL of oil, or almost 75 % of the ultimate oil recovery.
The field has been described previously by Knutson and Munro (1991), and Robertson (1993). Recent drilling data (more than 30 new wells) and new 3D seismic have updated the initial field descriptions. These data allow the mapping of two key unconformities, the Mid Cimmerian (Jt) event and a Base Callovian (Jb3) event. Reservoir facies models and isochore maps have also been developed, which together with the refined structural model, allow a better understanding of the reservoir distributions and will guide future production strategies.